Problem: Simplify the following expression: $x = \dfrac{4}{8n + 4} \div \dfrac{10}{4n}$
Explanation: Dividing by an expression is the same as multiplying by its inverse. $x = \dfrac{4}{8n + 4} \times \dfrac{4n}{10}$ When multiplying fractions, we multiply the numerators and the denominators. $x = \dfrac{ 4 \times 4n } { (8n + 4) \times 10}$ $x = \dfrac{16n}{80n + 40}$ Simplify: $x = \dfrac{2n}{10n + 5}$